背景:积累的秸秆缓慢分解会降低水稻的生长,与水稻争夺土壤氮素养分。最近一年,可以加速秸秆分解的秸秆分解孕育剂(SDI)和可以快速产生可用N的铵态氮(N)肥料在中国越来越多地被采用。然而,通过共同施用SDI和氮铵肥料,是否可以同时满足秸秆分解和作物生长的氮需求仍然未知。
结果:在这项研究中,我们研究了共同施用SDI和碳酸氢铵对小麦秸秆分解速率的影响,稻麦轮作系统连续两年的水稻生长和水稻产量。使用复合肥(A0)作为对照。碳酸氢铵的添加比例为20%(A2),30%(A3)和40%(A4),分别,没有SDI或有SDI(IA2、IA3、IA4)。我们的结果显示,如果没有SDI,与A0相比,秸秆分解率,A2下水稻生长和产量得到了提高;然而,在A3下,由于秸秆分解速度慢和水稻生长后期有限,水稻产量下降。SDI和氮肥的组合提高了秸秆分解率,水稻的生长速度和产量超过单施氮肥,尤其是在IA3下。与A0相比,秸秆分解率,舵柄编号,地上生物量,叶面积指数,根长,氮素利用效率显著提高了16%,8%,27%,12%,17%,在IA3下占15%。因此,IA3的平均水稻产量提高到10856公斤/公顷,分别高出13%和9%,分别,比A0和A2。
结论:我们的结果表明,单独施用碳酸氢铵在生长后期有营养缺乏和产量下降的风险。因此,共同施用SDI和30%的氨氮肥料替代可以是同时加速秸秆分解和增加水稻作物生长的有利做法。
BACKGROUND: The growth of rice is reduced by the slow decomposition of accumulated straw, which competes with rice for soil nitrogen nutrient. In recent year, straw-decomposing inoculants (SDIs) that can accelerate straw decomposition and ammonium nitrogen (N) fertilizer that can quickly generate available N is increasingly adopted in China. However, it is still unknown whether the N demand of straw decomposition and crop growth can be simultaneously met through the co-application of SDIs and ammonium N fertilizer.
RESULTS: In this study, we investigated the effect of the co-application of SDIs and ammonium bicarbonate on decomposition rate of wheat straw, rice growth and rice yield over two consecutive years in rice-wheat rotation system. Compound fertilizer (A0) was used as control. The ratios of ammonium bicarbonate addition were 20% (A2), 30% (A3) and 40% (A4), respectively, without SDIs or with SDIs (IA2, IA3, IA4). Our results revealed that without SDIs, compared with A0, straw decomposition rate, rice growth and yield were improved under A2; However, under A3, rice yield was decreased due to the slow decomposition rate of straw and limited growth of rice during late growth stage. Combining SDIs and N fertilizer increased straw decomposition rate, rice growth rate and yield more than that of N fertilizer alone, especially under IA3. Compared with A0, straw decomposition rate, tiller number, aboveground biomass, leaf area index, root length, and nitrogen use efficiency were significantly increased by 16%, 8%, 27%, 12%, 17%, and 15% under IA3. Consequently, the average rice yield of IA3 was increased to 10,856 kg/ha, which was 13% and 9% higher, respectively, than of A0 and A2.
CONCLUSIONS: Our results indicated that ammonium bicarbonate application alone carried a risk of nutrient deficiency during late growth stage and yield decline. Therefore, the co-application of SDIs and 30% ammonium N fertilizer substitution can be a favorable practice to simultaneously accelerate straw decomposition and increase rice crop growth.